Hello Karima,
Here is the error attached I encountered while evolving black holes binary. The work-around I guess is to increase the number of processes (if I am not wrong), but I am not quite sure how to do that. I need some help to get around this issue.
Assuming you use simulation factory you need to pass options to make sure it creates multiple MPI processes. The auto-detection code tends to choose a number of threads equal to the the number of cores on your laptop and and a single MPI rank.
Eg if you have a 4 core laptop then you have to use:
./simfactory/bin/sim submit testrun01 --cores 4 --num-threads 2 --parfile ...
which uses a total of 4 cores and starts 2 threads per MPI rank so that you end up with 4 / 2 = 2 MPI ranks each of which uses 2 threads.
Similarly on clusters, the basic idea is to set --num-threads so that there are more than 1 MPI rank started (ie --num-threads is larger than the value for --cores or --procs [which are synonyms for each other]).
If not using simulation factory you have to manually use mpirun and OMP_NUM_THREADS. Eg:
export OMP_NUM_THREADS=2
mpirun -np 2 /home/karima/simulations/bbhHr/SIMFACTORY/exe/cactus_sim -L 3 /home/karima/simulations/bbhHr/output-0000/BBHHigherRes.par
which starts 2 MPI ranks each will use 2 OpenMP threads.
Yours, Roland